1. Field of the Invention
The present invention relates to a fully rotating hook for a lockstitch sewing machine, such as a vertically fully rotating hook and a vertical axis fully rotating hook.
2. Description of the Related Art
Since a conventional fully rotating hook for a sewing machine is made of steel, there is a large coefficient of friction between a track projection of an inner bobbin case holder (hereinafter, often referred to merely as "bobbin case holder") and a track groove of an outer loop taker into which the track projection is fitted. In order to improve sewing quality, it is required to reduce the torque necessary for rotating the outer loop taker.